Spatial and temporal scales of distribution and demography in breeding songbirds: implications of habitat fragmentation and restoration

dc.contributor.advisor Rolf R. Koford
dc.contributor.author Fletcher, Robert
dc.contributor.department Natural Resource Ecology and Management
dc.date 2018-08-25T00:30:24.000
dc.date.accessioned 2020-07-02T05:50:22Z
dc.date.available 2020-07-02T05:50:22Z
dc.date.copyright Wed Jan 01 00:00:00 UTC 2003
dc.date.issued 2003-01-01
dc.description.abstract <p>Tallgrass prairie has declined throughout the midwestern United States during the past two centuries, and migratory birds breeding in these habitats have also experienced precipitous population declines. One conservation strategy used to mitigate the effects of habitat loss and fragmentation is habitat restoration. I studied how both habitat fragmentation and restoration affect songbird populations breeding in grassland and wetland habitats in northern Iowa, 1999--2002. Most grassland birds tended to be less abundant near edges, yet birds avoided woodland edges more so than other types of edges. Edge avoidance could not be explained by changes in habitat structure. For Bobolinks (Dolichonyx oryzivorus), edge avoidance also increased near corners of sites, where multiple edges converged. These local patterns of edge avoidance were consistent with observed patterns of area sensitivity when scaling patterns up to fragmented landscapes using simulation modeling in neutral (randomized) landscapes. Moreover, regression modeling at landscape scales suggested that edge density metrics were better than landscape compositional metrics at explaining bird density within patches. Habitat restoration provided breeding habitat for many bird species, in which birds tended to occur at high densities in restored patches relative to other land cover types in the landscape. However, demographic data revealed a more complex pattern. In restored wetlands, reproduction was tied closely to interannual climate variation. In particular, nest predation was negatively correlated with water depth in wetlands. In restored grasslands, nest success tended to be relatively low for most species. Population projection models suggested that for Dickcissels (Spiza americana) and, to a lesser extent, Bobolinks, population growth rates were not high enough to be sustainable without immigration into the area (lambda < 1). In addition, population growth was most sensitive to adult survival. Sensitivity to nest predation was moderate and dependent on estimates of survival, while growth was less sensitive to brood parasitism and juvenile survival. Results from this study have improved our understanding of the role of edge effects in generating spatial distributions in landscapes, how restoration ultimately affects avian populations in the Midwest, and it provides a framework for understanding songbird dynamics in fragmented landscapes.</p>
dc.format.mimetype application/pdf
dc.identifier archive/lib.dr.iastate.edu/rtd/579/
dc.identifier.articleid 1578
dc.identifier.contextkey 6075521
dc.identifier.doi https://doi.org/10.31274/rtd-180813-11499
dc.identifier.s3bucket isulib-bepress-aws-west
dc.identifier.submissionpath rtd/579
dc.identifier.uri https://dr.lib.iastate.edu/handle/20.500.12876/78484
dc.language.iso en
dc.source.bitstream archive/lib.dr.iastate.edu/rtd/579/r_3085904.pdf|||Sat Jan 15 01:00:30 UTC 2022
dc.subject.disciplines Ecology and Evolutionary Biology
dc.subject.disciplines Environmental Sciences
dc.subject.disciplines Forest Sciences
dc.subject.disciplines Natural Resources and Conservation
dc.subject.disciplines Natural Resources Management and Policy
dc.subject.disciplines Zoology
dc.subject.keywords Natural resource ecology and management
dc.subject.keywords Ecology and evolutionary biology
dc.title Spatial and temporal scales of distribution and demography in breeding songbirds: implications of habitat fragmentation and restoration
dc.type article
dc.type.genre dissertation
dspace.entity.type Publication
relation.isOrgUnitOfPublication e87b7b9d-30ea-4978-9fb9-def61b4010ae
thesis.degree.discipline Ecology and Evolutionary Biology
thesis.degree.level dissertation
thesis.degree.name Doctor of Philosophy
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